The Conservatives are set to make an "unambiguous commitment" to giving more funds to public services.
The Tories say ministers must stop "beating up" on staff
A Tory policy group has called for the promise as part of David Cameron's new approach to education and health.
And the party's policy chief, Oliver Letwin, says the shadow cabinet is "almost certain" to back the demand.
It comes despite right-wing Tories urging Mr Cameron to make the "moral case" for lower taxes. Mr Letwin denied the two calls contradicted each other.
But Labour claims the Tories are just putting a new gloss on old policies.
The public service improvement policy group, one of six commissions appointed by Mr Cameron, has published an interim report.
The Wellbeing of the Nation report says economic growth is a means to better quality of life, not an end in itself.
"We believe that all Conservatives should embrace an unambiguous commitment to the growth of public services, as part of a growth of general well being," it says.
"As we get richer, we expect to spend a significant share of our additional national income on improving education, enhancing healthcare, supporting the elderly and looking after the disadvantaged."
Former chief schools inspector Baroness Perry, who co-chaired the policy group, said the public must be shown how the extra money was spent.
At a briefing for reporters in central London, Mr Letwin said the shadow cabinet would look very carefully at the call and "will almost certainly want to back" it.
However, the right-wing No Turning Back Group is proposing possible cuts to inheritance tax, income tax, stamp duty on homes and capital gains tax.
In a foreword to the pamphlet, former Cabinet minister John Redwood, said: "This is a plea for early action to cut our tax rates.
"If you keep tax rates down, the economy grows much quicker.
"Lower taxes are not a desirable extra you can add when everything is fine. Lower tax rates are the way to get everything going well."
Mr Letwin said there was no contradiction between the two themes.
The Conservatives were already promising to share the proceeds from growth in the economy between spending on public services and lower taxes.
"Of course we accept that lower and simpler taxes are part of what tends to make an open economy grow faster," he said.
But he warned that stability had to be put above tax cuts.
Labour Chief Secretary to the Treasury Stephen Timms said the Conservative approach to public services remained unchanged despite the "warm words".
"The Tories are committed as a matter of policy to reducing the share of national income spent on public services over the course of the economic cycle, a policy that would have meant spending £17bn less this year on public services," he said.
The Tory policy group also calls for a major shift in attitudes towards people who work in schools, hospitals and other public services.
It says there should be a "new partnership with the professions".
"A private corporation which publicly shamed its employees in the way that government has done in recent years would not long survive," it says.
The group also argues: "There has been a vastly overstated focus on what the public sector can learn from the private sector."
The group wants to limit the amount of inspections and testing in schools, with fewer exams, and give teachers more power to set their own targets.